Originally Posted by david s poole

based on your info,i would think that your problem lies with the bolts that hold down the rocker assemblies.the head is aluminum and the bolts are steel and one or more of the bolts [probably on one assembly] have pulled loose.there are two choices.find the bolt[s] with the pulled threads and buy some bolts that are 10mm longer [at the threads]and you can take advantage of the extra unused threads at the bottom of the hole.tighten to about 15ft/lbs.or to do the job correctly,buy a helicoil kit and redo the damaged holes.this is a permanent fix.you can do this job yourself.good luck.